Integration of Distributed Solar Energy into Saudi Smart Distribution Grids: Voltage Regulation, Hosting Capacity and Protection Challenges

Abstract

The deployment of distributed solar photovoltaic generation is leading Saudi Arabia's distribution networks to move from a primarily one-way arrangement to a more actively managed system in which power, voltage and fault current can change direction at various stages of operation. This study looks at the technical integration of distributed solar energy into Saudi smart distribution grids by considering three closely related areas: voltage regulation, hosting capacity and protection. Synthetic data from 2020 to 2025 is examined with particular regard to the specific circumstances in Saudi Arabia, the latest grid-connection requirements, international research on distribution networks and advanced control techniques. The review argues that it is not feasible to control photovoltaic penetration by means of a single static capacity limit because the limiting factor varies according to the feeder impedance, the level of load coincidence, inverter behaviour, network topology, weather conditions, protection settings and the available flexibility. Even though smart inverters, on-load tap changers that are coordinated, battery storage, demand response and data-driven hosting-capacity tools can increase the amount of power that the network is able to take in, the benefits of these measures depend on interoperable settings and protection-aware operation. There are also additional design problems in Saudi Arabia due to high levels of irradiance, temperature, dust, the concentration of solar generation during the midday and the rapid growth in distributed resources. It is therefore proposed that a comprehensive planning framework be adopted in which the voltage, thermal, power quality and protection limits are jointly assessed across time-series scenarios, following which coordinated control and adaptive protection are put into place. The review also points out key areas that require further research, namely feeder-level data from Saudi Arabia, probabilistic hosting capacity, the interaction between inverters and protection systems, digital monitoring and field validation.